SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) Amendment No. ZONAGEN, INC. -------------------------------------------------------------------------------- (Name of Issuer) -------------------------------------------------------------------------------- (Title of Class of Securities) 98975L108 -------------------------------------------------------------------------------- (CUSIP Number) MAY 23, 2005 -------------------------------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: |_| Rule 13d-1(b) |X| Rule 13d-1(c) |_| Rule 13d-1(d) ---------- (1) The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 98975L108 13G Page 2 of 12 Pages -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) ProMed Partners, L.P. -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |X| (b) |_| -------------------------------------------------------------------------------- 3. SEC USE ONLY -------------------------------------------------------------------------------- 4. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- NUMBER OF 5. SOLE VOTING POWER SHARES 95,582 ----------------------------------------------------------------- BENEFICIALLY 6. SHARED VOTING POWER OWNED BY ----------------------------------------------------------------- EACH 7. SOLE DISPOSITIVE POWER REPORTING 95,582 ----------------------------------------------------------------- PERSON 8. SHARED DISPOSITIVE POWER WITH -------------------------------------------------------------------------------- 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 95,582 -------------------------------------------------------------------------------- 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 .9% -------------------------------------------------------------------------------- 12. TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 98975L108 13G Page 3 of 12 Pages -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) ProMed Partners II, L.P. -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |X| (b) |_| -------------------------------------------------------------------------------- 3. SEC USE ONLY -------------------------------------------------------------------------------- 4. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- NUMBER OF 5. SOLE VOTING POWER SHARES 25,034 ----------------------------------------------------------------- BENEFICIALLY 6. SHARED VOTING POWER OWNED BY ----------------------------------------------------------------- EACH 7. SOLE DISPOSITIVE POWER REPORTING 25,034 ----------------------------------------------------------------- PERSON 8. SHARED DISPOSITIVE POWER WITH -------------------------------------------------------------------------------- 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 25,034 -------------------------------------------------------------------------------- 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 .25% -------------------------------------------------------------------------------- 12. TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 98975L108 13G Page 4 of 12 Pages -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) ProMed Offshore Fund, Ltd. -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |X| (b) |_| -------------------------------------------------------------------------------- 3. SEC USE ONLY -------------------------------------------------------------------------------- 4. CITIZENSHIP OR PLACE OF ORGANIZATION British Virgin Islands -------------------------------------------------------------------------------- NUMBER OF 5. SOLE VOTING POWER SHARES 15,800 ----------------------------------------------------------------- BENEFICIALLY 6. SHARED VOTING POWER OWNED BY ----------------------------------------------------------------- EACH 7. SOLE DISPOSITIVE POWER REPORTING 15,800 ----------------------------------------------------------------- PERSON 8. SHARED DISPOSITIVE POWER WITH -------------------------------------------------------------------------------- 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 15,800 -------------------------------------------------------------------------------- 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 .15% -------------------------------------------------------------------------------- 12. TYPE OF REPORTING PERSON* CO -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 98975L108 13G Page 5 of 12 Pages -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) ProMed Offshore Fund II, Ltd. -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |X| (b) |_| -------------------------------------------------------------------------------- 3. SEC USE ONLY -------------------------------------------------------------------------------- 4. CITIZENSHIP OR PLACE OF ORGANIZATION British Virgin Islands -------------------------------------------------------------------------------- NUMBER OF 5. SOLE VOTING POWER SHARES 381,936 ----------------------------------------------------------------- BENEFICIALLY 6. SHARED VOTING POWER OWNED BY ----------------------------------------------------------------- EACH 7. SOLE DISPOSITIVE POWER REPORTING 381,936 ----------------------------------------------------------------- PERSON 8. SHARED DISPOSITIVE POWER WITH -------------------------------------------------------------------------------- 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 381,936 -------------------------------------------------------------------------------- 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 3.8% -------------------------------------------------------------------------------- 12. TYPE OF REPORTING PERSON* CO -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 98975L108 13G Page 6 of 12 Pages -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) ProMed Asset Management, L.L.C. -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |X| (b) |_| -------------------------------------------------------------------------------- 3. SEC USE ONLY -------------------------------------------------------------------------------- 4. CITIZENSHIP OR PLACE OF ORGANIZATION Massachusetts -------------------------------------------------------------------------------- NUMBER OF 5. SOLE VOTING POWER SHARES 120,616 ----------------------------------------------------------------- BENEFICIALLY 6. SHARED VOTING POWER OWNED BY ----------------------------------------------------------------- EACH 7. SOLE DISPOSITIVE POWER REPORTING 120,616 ----------------------------------------------------------------- PERSON 8. SHARED DISPOSITIVE POWER WITH -------------------------------------------------------------------------------- 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 120,616 (Reporting person disclaims beneficial ownership of shares held by ProMed Partners, L.P. and ProMed Partners II, L.P. which represent the interests of other partners of these entities.) -------------------------------------------------------------------------------- 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 1.15% -------------------------------------------------------------------------------- 12. TYPE OF REPORTING PERSON* IA -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 98975L108 13G Page 7 of 12 Pages -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) ProMed Management, Inc. -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |X| (b) |_| -------------------------------------------------------------------------------- 3. SEC USE ONLY -------------------------------------------------------------------------------- 4. CITIZENSHIP OR PLACE OF ORGANIZATION Massachusetts -------------------------------------------------------------------------------- NUMBER OF 5. SOLE VOTING POWER SHARES 397,736 ----------------------------------------------------------------- BENEFICIALLY 6. SHARED VOTING POWER OWNED BY ----------------------------------------------------------------- EACH 7. SOLE DISPOSITIVE POWER REPORTING 397,736 ----------------------------------------------------------------- PERSON 8. SHARED DISPOSITIVE POWER WITH -------------------------------------------------------------------------------- 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 397,736 (Reporting person disclaims beneficial ownership of shares held by ProMed Offshore Fund, Ltd. and ProMed OffShore Fund II, Ltd. which represent the interests of the shareholders of ProMed Offshore Fund, Ltd. and ProMed Offshore Fund II, Ltd.) -------------------------------------------------------------------------------- 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 3.95% -------------------------------------------------------------------------------- 12. TYPE OF REPORTING PERSON* IA -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! Page 8 of 12 Pages Item 1(a). Name of Issuer: Zonagen, Inc. -------------------------------------------------------------------------------- Item 1(b). Address of Issuer's Principal Executive Offices: 2408 Timberloch Place, Suite B-1, Woodlands, TX 77380 -------------------------------------------------------------------------------- Item 2(a). Name of Person Filing: ProMed Partners, L.P., ProMed Partners II, L.P., ProMed Offshore Fund, Ltd., ProMed OffShore Fund II, Ltd., ProMed Management, Inc., and ProMed Asset Management, L.L.C., -------------------------------------------------------------------------------- Item 2(b). Address of Principal Business Office, or if None, Residence: 125 Cambridgepark Drive, Cambridge, MA 02140 -------------------------------------------------------------------------------- Item 2(c). Citizenship: See pages 2,3,4,5,6,7 and 8 -------------------------------------------------------------------------------- Item 2(d). Title of Class of Securities: Common Stock -------------------------------------------------------------------------------- Item 2(e). CUSIP Number: 98975L108 -------------------------------------------------------------------------------- Item 3. If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a: (a) |_| Broker or dealer registered under Section 15 of the Exchange Act. (b) |_| Bank as defined in Section 3(a)(6) of the Exchange Act. (c) |_| Insurance company as defined in Section 3(a)(19) of the Exchange Act. (d) |_| Investment company registered under Section 8 of the Investment Company Act. (e) |_| An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E); (f) |_| An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F); (g) |_| A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G); (h) |_| A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act; (i) |_| A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act; (j) |_| Group, in accordance with Rule 13d-1(b)(1)(ii)(J). If this statement is filed pursuant to Rule 13d-1(c), check this box |X| Page 9 of 12 Pages Item 4. Ownership. Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1. (a) Amount beneficially owned: See pages 2,3,4,5,6,7 and 8 (b) Percent of class: See pages 2,3,4,5,6,7 and 8 (c) Number of shares as to which such person has: (i) Sole power to vote or to direct the vote See pages 2,3,4,5,6,7 and 8 (ii) Shared power to vote or to direct the vote See pages 2,3,4,5,6,7 and 8 (iii) Sole power to dispose or to direct the disposition of See pages 2,3,4,5,6,7 and 8 (iv) Shared power to dispose or to direct the disposition of See pages 2,3,4,5,6,7 and 8 -------------------------------------------------------------------------------- Item 5. Ownership of Five Percent or Less of a Class. Not Applicable -------------------------------------------------------------------------------- Item 6. Ownership of More Than Five Percent on Behalf of Another Person. Not Applicable -------------------------------------------------------------------------------- Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company. Not Applicable -------------------------------------------------------------------------------- Item 8. Identification and Classification of Members of the Group. See "Exhibit A" attached hereto and pages 2, 3, 4, 5, 6, 7 and 8 -------------------------------------------------------------------------------- Item 9. Notice of Dissolution of Group. Not Applicable -------------------------------------------------------------------------------- Item 10. Certifications. (a) The following certification shall be included if the statement is filed pursuant to Rule 13d-1(b): "By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having such purpose or effect." (b) The following certification shall be included if the statement is filed pursuant to Rule 13d-1(c): "By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having such purpose or effect." Page 10 of 12 Pages SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. June 7, 2005 ---------------------------------------- (Date) /s/ David B. Musket ---------------------------------------- (Signature) David B. Musket, President of Managing Member of the General Partner ---------------------------------------- (Name/Title) Note. Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7(b) for other parties for whom copies are to be sent. Attention. Intentional misstatements or omissions of fact constitute federal criminal violations (see 18 U.S.C. 1001). Schedule 13 G Page 11 of 12 CUSIP No. 98975L108 Index to Exhibits Exhibit Page No. ------- -------- Exhibit A -- Joint Filing Agreement, dated June 7, 2005 12 Schedule 13 G Page 12 of 12 CUSIP No. 98975L108 EXHIBIT A JOINT FILING AGREEMENT ProMed Partners, L.P., ProMed Partners II, L.P., ProMed Offshore Fund, Ltd., ProMed Offshore Fund II, Ltd. ProMed Management, Inc., and ProMed Asset Management, LLC, each hereby agrees that the Schedule 13G to which this Exhibit is attached and any amendments thereto relating to the acquisition of Shares of Common Stock of Orion Acquisition Corp.is filed jointly on behalf of each such person. Dated: June 7, 2005 PROMED PARTNERS, L.P. By: ProMed Asset Management, LLC its General Partner By: DBM Corporate Consulting Group, Ltd, a Managing Member By: /s/ David B. Musket -------------------------------------- David B. Musket Director PROMED PARTNERS, II, L.P. By: ProMed Asset Management, LLC its General Partner By: DBM Corporate Consulting Group, Ltd. a Managing Member By: /s/ David B. Musket -------------------------------------- David B. Musket Director PROMED OFFSHORE FUND, LTD. By: /s/ David B. Musket -------------------------------------- David B. Musket Director PROMED OFFSHORE FUND II, LTD. By: /s/ David B. Musket -------------------------------------- David B. Musket Director PROMED MANAGEMENT, INC. By: /s/ David B. Musket -------------------------------------- David B. Musket President PROMED ASSET MANAGEMENT, LLC By: DBM Corporate Consulting Group, Ltd. A Managing Member By: /s/ David B. Musket -------------------------------------- David B. Musket President